There is a known lathe turning tool referred to as a rotary cutting tool, a spinning tool, and the like that is used in the above-mentioned processing scheme. An example of such a lathe turning tool is, for example, disclosed in Japanese Patent National Publication No. 2007-504011 as described below.
The lathe turning tool disclosed in this document has two structures for attachment of a cutting insert. One of the structures is as follows: a collet is inserted into a hole at the end of a tool holder (a tool main body), a portion of the collet protruding from the tool holder is inserted into an attachment hole in the center of the cutting insert, and this protruding portion is screwed into the collet through the attachment hole in the center of the cutting insert, to cause an increase in diameter by a bolt so as to be functioned as a so-called inner diameter chuck for fixing the cutting insert.
The cutting insert is provided on its bottom surface (seat face) with a protrusion, which is fitted into a concave portion provided in the bearing surface at the end of the tool holder, so that this cutting insert is prevented from rotating.
The other one of the attachment structures is as follows: a cutting insert is provided with an attachment portion having a truncated conical shape, and this attachment portion is inserted into a fitting bore provided at the end of the tool main body (a tool holder) for fixing the cutting insert.